mm/memory_hotplug: make remove_memory() take the device_hotplug_lock
[muen/linux.git] / drivers / acpi / acpi_memhotplug.c
1 /*
2  * Copyright (C) 2004, 2013 Intel Corporation
3  * Author: Naveen B S <naveen.b.s@intel.com>
4  * Author: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
5  *
6  * All rights reserved.
7  *
8  * This program is free software; you can redistribute it and/or modify
9  * it under the terms of the GNU General Public License as published by
10  * the Free Software Foundation; either version 2 of the License, or (at
11  * your option) any later version.
12  *
13  * This program is distributed in the hope that it will be useful, but
14  * WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
16  * NON INFRINGEMENT.  See the GNU General Public License for more
17  * details.
18  *
19  * ACPI based HotPlug driver that supports Memory Hotplug
20  * This driver fields notifications from firmware for memory add
21  * and remove operations and alerts the VM of the affected memory
22  * ranges.
23  */
24
25 #include <linux/acpi.h>
26 #include <linux/memory.h>
27 #include <linux/memory_hotplug.h>
28
29 #include "internal.h"
30
31 #define ACPI_MEMORY_DEVICE_CLASS                "memory"
32 #define ACPI_MEMORY_DEVICE_HID                  "PNP0C80"
33 #define ACPI_MEMORY_DEVICE_NAME                 "Hotplug Mem Device"
34
35 #define _COMPONENT              ACPI_MEMORY_DEVICE_COMPONENT
36
37 #undef PREFIX
38 #define         PREFIX          "ACPI:memory_hp:"
39
40 ACPI_MODULE_NAME("acpi_memhotplug");
41
42 static const struct acpi_device_id memory_device_ids[] = {
43         {ACPI_MEMORY_DEVICE_HID, 0},
44         {"", 0},
45 };
46
47 #ifdef CONFIG_ACPI_HOTPLUG_MEMORY
48
49 /* Memory Device States */
50 #define MEMORY_INVALID_STATE    0
51 #define MEMORY_POWER_ON_STATE   1
52 #define MEMORY_POWER_OFF_STATE  2
53
54 static int acpi_memory_device_add(struct acpi_device *device,
55                                   const struct acpi_device_id *not_used);
56 static void acpi_memory_device_remove(struct acpi_device *device);
57
58 static struct acpi_scan_handler memory_device_handler = {
59         .ids = memory_device_ids,
60         .attach = acpi_memory_device_add,
61         .detach = acpi_memory_device_remove,
62         .hotplug = {
63                 .enabled = true,
64         },
65 };
66
67 struct acpi_memory_info {
68         struct list_head list;
69         u64 start_addr;         /* Memory Range start physical addr */
70         u64 length;             /* Memory Range length */
71         unsigned short caching; /* memory cache attribute */
72         unsigned short write_protect;   /* memory read/write attribute */
73         unsigned int enabled:1;
74 };
75
76 struct acpi_memory_device {
77         struct acpi_device * device;
78         unsigned int state;     /* State of the memory device */
79         struct list_head res_list;
80 };
81
82 static acpi_status
83 acpi_memory_get_resource(struct acpi_resource *resource, void *context)
84 {
85         struct acpi_memory_device *mem_device = context;
86         struct acpi_resource_address64 address64;
87         struct acpi_memory_info *info, *new;
88         acpi_status status;
89
90         status = acpi_resource_to_address64(resource, &address64);
91         if (ACPI_FAILURE(status) ||
92             (address64.resource_type != ACPI_MEMORY_RANGE))
93                 return AE_OK;
94
95         list_for_each_entry(info, &mem_device->res_list, list) {
96                 /* Can we combine the resource range information? */
97                 if ((info->caching == address64.info.mem.caching) &&
98                     (info->write_protect == address64.info.mem.write_protect) &&
99                     (info->start_addr + info->length == address64.address.minimum)) {
100                         info->length += address64.address.address_length;
101                         return AE_OK;
102                 }
103         }
104
105         new = kzalloc(sizeof(struct acpi_memory_info), GFP_KERNEL);
106         if (!new)
107                 return AE_ERROR;
108
109         INIT_LIST_HEAD(&new->list);
110         new->caching = address64.info.mem.caching;
111         new->write_protect = address64.info.mem.write_protect;
112         new->start_addr = address64.address.minimum;
113         new->length = address64.address.address_length;
114         list_add_tail(&new->list, &mem_device->res_list);
115
116         return AE_OK;
117 }
118
119 static void
120 acpi_memory_free_device_resources(struct acpi_memory_device *mem_device)
121 {
122         struct acpi_memory_info *info, *n;
123
124         list_for_each_entry_safe(info, n, &mem_device->res_list, list)
125                 kfree(info);
126         INIT_LIST_HEAD(&mem_device->res_list);
127 }
128
129 static int
130 acpi_memory_get_device_resources(struct acpi_memory_device *mem_device)
131 {
132         acpi_status status;
133
134         if (!list_empty(&mem_device->res_list))
135                 return 0;
136
137         status = acpi_walk_resources(mem_device->device->handle, METHOD_NAME__CRS,
138                                      acpi_memory_get_resource, mem_device);
139         if (ACPI_FAILURE(status)) {
140                 acpi_memory_free_device_resources(mem_device);
141                 return -EINVAL;
142         }
143
144         return 0;
145 }
146
147 static int acpi_memory_check_device(struct acpi_memory_device *mem_device)
148 {
149         unsigned long long current_status;
150
151         /* Get device present/absent information from the _STA */
152         if (ACPI_FAILURE(acpi_evaluate_integer(mem_device->device->handle,
153                                                METHOD_NAME__STA, NULL,
154                                                &current_status)))
155                 return -ENODEV;
156         /*
157          * Check for device status. Device should be
158          * present/enabled/functioning.
159          */
160         if (!((current_status & ACPI_STA_DEVICE_PRESENT)
161               && (current_status & ACPI_STA_DEVICE_ENABLED)
162               && (current_status & ACPI_STA_DEVICE_FUNCTIONING)))
163                 return -ENODEV;
164
165         return 0;
166 }
167
168 static unsigned long acpi_meminfo_start_pfn(struct acpi_memory_info *info)
169 {
170         return PFN_DOWN(info->start_addr);
171 }
172
173 static unsigned long acpi_meminfo_end_pfn(struct acpi_memory_info *info)
174 {
175         return PFN_UP(info->start_addr + info->length-1);
176 }
177
178 static int acpi_bind_memblk(struct memory_block *mem, void *arg)
179 {
180         return acpi_bind_one(&mem->dev, arg);
181 }
182
183 static int acpi_bind_memory_blocks(struct acpi_memory_info *info,
184                                    struct acpi_device *adev)
185 {
186         return walk_memory_range(acpi_meminfo_start_pfn(info),
187                                  acpi_meminfo_end_pfn(info), adev,
188                                  acpi_bind_memblk);
189 }
190
191 static int acpi_unbind_memblk(struct memory_block *mem, void *arg)
192 {
193         acpi_unbind_one(&mem->dev);
194         return 0;
195 }
196
197 static void acpi_unbind_memory_blocks(struct acpi_memory_info *info)
198 {
199         walk_memory_range(acpi_meminfo_start_pfn(info),
200                           acpi_meminfo_end_pfn(info), NULL, acpi_unbind_memblk);
201 }
202
203 static int acpi_memory_enable_device(struct acpi_memory_device *mem_device)
204 {
205         acpi_handle handle = mem_device->device->handle;
206         int result, num_enabled = 0;
207         struct acpi_memory_info *info;
208         int node;
209
210         node = acpi_get_node(handle);
211         /*
212          * Tell the VM there is more memory here...
213          * Note: Assume that this function returns zero on success
214          * We don't have memory-hot-add rollback function,now.
215          * (i.e. memory-hot-remove function)
216          */
217         list_for_each_entry(info, &mem_device->res_list, list) {
218                 if (info->enabled) { /* just sanity check...*/
219                         num_enabled++;
220                         continue;
221                 }
222                 /*
223                  * If the memory block size is zero, please ignore it.
224                  * Don't try to do the following memory hotplug flowchart.
225                  */
226                 if (!info->length)
227                         continue;
228                 if (node < 0)
229                         node = memory_add_physaddr_to_nid(info->start_addr);
230
231                 result = add_memory(node, info->start_addr, info->length);
232
233                 /*
234                  * If the memory block has been used by the kernel, add_memory()
235                  * returns -EEXIST. If add_memory() returns the other error, it
236                  * means that this memory block is not used by the kernel.
237                  */
238                 if (result && result != -EEXIST)
239                         continue;
240
241                 result = acpi_bind_memory_blocks(info, mem_device->device);
242                 if (result) {
243                         acpi_unbind_memory_blocks(info);
244                         return -ENODEV;
245                 }
246
247                 info->enabled = 1;
248
249                 /*
250                  * Add num_enable even if add_memory() returns -EEXIST, so the
251                  * device is bound to this driver.
252                  */
253                 num_enabled++;
254         }
255         if (!num_enabled) {
256                 dev_err(&mem_device->device->dev, "add_memory failed\n");
257                 mem_device->state = MEMORY_INVALID_STATE;
258                 return -EINVAL;
259         }
260         /*
261          * Sometimes the memory device will contain several memory blocks.
262          * When one memory block is hot-added to the system memory, it will
263          * be regarded as a success.
264          * Otherwise if the last memory block can't be hot-added to the system
265          * memory, it will be failure and the memory device can't be bound with
266          * driver.
267          */
268         return 0;
269 }
270
271 static void acpi_memory_remove_memory(struct acpi_memory_device *mem_device)
272 {
273         acpi_handle handle = mem_device->device->handle;
274         struct acpi_memory_info *info, *n;
275         int nid = acpi_get_node(handle);
276
277         list_for_each_entry_safe(info, n, &mem_device->res_list, list) {
278                 if (!info->enabled)
279                         continue;
280
281                 if (nid == NUMA_NO_NODE)
282                         nid = memory_add_physaddr_to_nid(info->start_addr);
283
284                 acpi_unbind_memory_blocks(info);
285                 __remove_memory(nid, info->start_addr, info->length);
286                 list_del(&info->list);
287                 kfree(info);
288         }
289 }
290
291 static void acpi_memory_device_free(struct acpi_memory_device *mem_device)
292 {
293         if (!mem_device)
294                 return;
295
296         acpi_memory_free_device_resources(mem_device);
297         mem_device->device->driver_data = NULL;
298         kfree(mem_device);
299 }
300
301 static int acpi_memory_device_add(struct acpi_device *device,
302                                   const struct acpi_device_id *not_used)
303 {
304         struct acpi_memory_device *mem_device;
305         int result;
306
307         if (!device)
308                 return -EINVAL;
309
310         mem_device = kzalloc(sizeof(struct acpi_memory_device), GFP_KERNEL);
311         if (!mem_device)
312                 return -ENOMEM;
313
314         INIT_LIST_HEAD(&mem_device->res_list);
315         mem_device->device = device;
316         sprintf(acpi_device_name(device), "%s", ACPI_MEMORY_DEVICE_NAME);
317         sprintf(acpi_device_class(device), "%s", ACPI_MEMORY_DEVICE_CLASS);
318         device->driver_data = mem_device;
319
320         /* Get the range from the _CRS */
321         result = acpi_memory_get_device_resources(mem_device);
322         if (result) {
323                 device->driver_data = NULL;
324                 kfree(mem_device);
325                 return result;
326         }
327
328         /* Set the device state */
329         mem_device->state = MEMORY_POWER_ON_STATE;
330
331         result = acpi_memory_check_device(mem_device);
332         if (result) {
333                 acpi_memory_device_free(mem_device);
334                 return 0;
335         }
336
337         result = acpi_memory_enable_device(mem_device);
338         if (result) {
339                 dev_err(&device->dev, "acpi_memory_enable_device() error\n");
340                 acpi_memory_device_free(mem_device);
341                 return result;
342         }
343
344         dev_dbg(&device->dev, "Memory device configured by ACPI\n");
345         return 1;
346 }
347
348 static void acpi_memory_device_remove(struct acpi_device *device)
349 {
350         struct acpi_memory_device *mem_device;
351
352         if (!device || !acpi_driver_data(device))
353                 return;
354
355         mem_device = acpi_driver_data(device);
356         acpi_memory_remove_memory(mem_device);
357         acpi_memory_device_free(mem_device);
358 }
359
360 static bool __initdata acpi_no_memhotplug;
361
362 void __init acpi_memory_hotplug_init(void)
363 {
364         if (acpi_no_memhotplug) {
365                 memory_device_handler.attach = NULL;
366                 acpi_scan_add_handler(&memory_device_handler);
367                 return;
368         }
369         acpi_scan_add_handler_with_hotplug(&memory_device_handler, "memory");
370 }
371
372 static int __init disable_acpi_memory_hotplug(char *str)
373 {
374         acpi_no_memhotplug = true;
375         return 1;
376 }
377 __setup("acpi_no_memhotplug", disable_acpi_memory_hotplug);
378
379 #else
380
381 static struct acpi_scan_handler memory_device_handler = {
382         .ids = memory_device_ids,
383 };
384
385 void __init acpi_memory_hotplug_init(void)
386 {
387         acpi_scan_add_handler(&memory_device_handler);
388 }
389
390 #endif /* CONFIG_ACPI_HOTPLUG_MEMORY */